MINERAL RESOURCES OF THE STATE OF NEW YORK 



67 



ores in the American markets. Ordinarily the home requirements 

 are supplied' mainly by importations of Grecian and Turkish emery, 

 and the small amotints mined here are employed in admixture with 

 the foreign ore which has come to be recognized as standard. The 

 imports in normal times from Turkey and Greece have averaged 

 about 15,000 long tons crude rock, worth from $i5-$2o a ton. In 

 1916 they dropped to 7511 tons ($102,459) and in 1917 to 650 tons 

 ($8875). 



The output of the Peekskill district, for the years for which statis- 

 tics are available, has been as follows : 



Production of emery in New York 



1-904 

 1905 

 1906 

 1907 

 1908 

 1909 

 19110 

 1911 

 1912 

 I-9.I3 

 1914 

 1915 

 191 6 



191 7. 



191 8. 



$17 220 



12 452 



13 870 



13 057 

 8 860 



10 780 



11 736 



8 810 



6 479 



7 332 



9 105 

 42 591 



123 901 



170 223 



61 660 



It will be seen that the output for the years 19 16 and 191 7 

 measured up practically to the quotas formerly derived from abroad. 



Occurrence. The Peekskill emery comes from the area of igneous 

 rocks southeast of that city, that collectively are known as the 

 Cortlandt series. They include a variety of types,, mainly of basic 

 nature, such as diorite, gabbro, norite, peridotite and pyroxenite 

 and altogether form a compact mass some 7 miles in east and west 

 extent by 5, miles north and south. The well-known Mohegan 

 granite lies on the northeast border and may represent an offshoot 

 of the same parent magma, as has been suggested by C. P. Berkey.^ 

 The geology and petrographic features of the area have been 

 described in much, detail by J. D. Dana, G. H. Williams and more 



^'•^ience, v. 28, 1908, p. 575. 



3 , . 



